This vulnerability affects: Adobe Reader and Acrobat 9 and earlier, on Windows, Mac, *nix computers
How an attacker exploits it: By enticing your users into viewing a maliciously crafted PDF document
Impact: An attacker can execute code on your computer, potentially gaining control of it
What to do: Implement the workarounds described in the Solutions section of this alert

The source jump from 40,000 to 80,000 with a large number of them originating in China. Recent tcp 2967 traffic appears to be related to an IRC BOT mostly aimed at colleges, but others, too. This following links give a rather good explanation of the exploit.